The present invention relates, in general, to a winding spool, and more specifically to a winding spool of a type including a hollow barrel with two flanges, whereby at least one of the flanges is detachably connected to the barrel by a bayonet coupling in the form of interacting retainer elements and locking elements formed on the barrel end and the inner flange wall, respectively, and so spaced apart as to allow interlocking of the detachable flange and the barrel end when rotating the bayonet coupling until reaching a lock position defined by a stop.
Winding spools of this type can be wound with materials of all kinds, especially wires, ropes, cables and the like and have been known for many years, for example, from International Patent Specification Nos. WO 9413569, WO 9413570, European Pat. No. EP 0 411 978 or German Pat. No. DE 79 35 978 U1. In conjunction with conical barrels or barrels that can be disassembled, the use of a separable attachment of at least one of the flanges to the barrel is advantageous because it reduces the need for space during transport of empty winding spools, in particular when the spools are returned by the consumer back to the provider for re-winding new material onto the barrel.
In certain situations, it may be desirable to temporarily secure the bayonet coupling by an additional locking mechanism, in particular when encountering during take-up phase and unwinding phase sudden accelerations or decelerations, in order to prevent a rotation between the flange and the barrel in release direction of the bayonet. Known constructions propose integration of latching members in the flange or the barrel for engagement into the gap of the bayonet coupling, i.e. between two locking elements or two retaining elements. When the flange and the barrel end are fitted into one another, the latching members are resiliently forced back, and spring back into the gaps when the bayonet coupling reaches the lock position to thereby secure the bayonet coupling against release.
Integration of such latching members is complicated in structure and expensive as far as production and installation in the flange are concerned. Moreover, in many cases, the securement between flange and barrel in axial direction of the winding spool by means of the bayonet coupling is sufficient, so that the use of such integrated locking members is not needed.